- Third Grade
- 50 minutes
- Standards: 3.NBT.A.3
Let students stretch their problem solving skills in this lesson that teaches them how to solve problems where one-digit numbers are multiplied by multiples of 10.
Students will be able to multiply one-digit whole numbers by multiples of 10.
Introduction (10 minutes)
- Explain to the class how it is good to know how to solve tricky math problems in your head instead of always having to write them down or use a calculator.
- Tell them that today they are going to learn the trick to multiply whole numbers by multiples of 10.
- Ask your students to solve the problem 10x5.
- Once students have solved the problem, ask them if they could solve 50x5 as quickly.
- Tell students that they will need to know how to solve these bigger equations someday.
- Give your students a real life example. For example, when planning a big party you might need 50 tables of 5 people each.
- Tell students that this skill will help them solve each of these problems quickly in their head.
Explicit Instruction/Teacher Modeling (10 minutes)
- Write several problems showing the concept of multiplying one-digit whole numbers by multiples of 10 on the board.
- Ask the students if they can find any pattern to solve these equations by looking at the equation and the answer.
- Have a few students share with the class about their patterns and ideas they see in the problems.
- Tell students that when they are multiplying numbers by multiples of 10, such as 10, 20, 30, 40, or 50, you can think of it as removing the zero and multiplying the two one-digit numbers together, then adding the zero back on to the answer.
- Refer to the examples you had previously written on the board. Solve one by walking through the steps in front of the class.
- Call on volunteers to help remind you of the steps as you solve another problem.
- Remind students that it doesn't matter whether or not the multiple of ten is the first or second number in the expression because the process and outcome will be the same.
Guided Practice/Interactive Modeling (10 minutes)
- Have students use mini whiteboards or scratch paper to complete practice problems together.
- Write out various problems for the class to solve together. Remind students to practice writing down their own answers on their whiteboard or scratch paper.
- Let students work in partners to try and solve the problems together first.
- Ask one group to share their answer for each equation. Ask the students, as they are sharing, how they found their answer and how they know it is correct.
Independent Working Time (10 minutes)
- Have students solve the Multiplying by 10 worksheet independently.
- Remind students to explain how they got their answers.
- Enrichment: Students who need an extra challenge should flip the worksheet over when they are finished and try to come up with their own problems involving multiplying one-digit numbers with multiples of 10.
- Support: Students who need more support can work on completing half of the problems on the worksheet or work with a partner who may have a better grasp of the concept.
Assessment (5 minutes)
- Hand out sticky notes to your students.
- Write two problems on the board, and have students answer them on the sticky note.
- Collect the sticky notes to check for understanding.
Review and Closing (5 minutes)
- Ask students why they think it is important to know how to solve these kinds of problems.
- Have students pair and share an explanation of how to solve these types of equations.